Conventionally, in communication networks, switches can be managed through abstract models. For example, cross connects in a switching fabric can be managed based on abstractions in software consistent with standards defined by the International Telecommunications Union (ITU) and Telecordia standards bodies. One such standard is ITU-T M.3100 “Generic network information model” (April 2005), the contents of which are incorporated by reference herein. In operation, the abstractions are used to manage physical connections in an actual switch. That is, the abstractions represent logical software objects managing real connections in hardware. Conventional abstraction systems and methods almost always utilize bidirectional circuits. While there are instances of a unidirectional connection made up of unidirectional Connection Termination Points (CTPs), these are always symmetric in nature, which means that if a timeslot in a Connection Termination Point (CTP) is participating in a concatenation group of a size m, in a transmit direction, then it cannot participate in another concatenation group of size n, different from m, which may belong to another connection. CTPs are logical connection points used for cross-connecting and automated provisioning of end-to-end circuits. For example, CTPs can include one or more STS-1 (Synchronous Transport Signal 1), VC-3 (Virtual Circuit 3), etc. time slots.
Another restriction is that even if the concatenation size is same, the head timeslot must be the same for every timeslot participating in that concatenation group, in both transmit and receive direction. This restriction applies to various simple connections (e.g., one-way, two-way, two-way protected and unprotected connections, etc.) as well as any flexible complex connections (FCCs). Hence conventional abstraction systems and methods are all symmetric traffic patterns. Both transmit and receive direction of every timeslot that belongs to any CTP can only be used with a same concatenation and remains with a same CTP in both directions. Thus, every timeslot in any CTP is coupled together in both transmit and receive directions. Disadvantageously, if only one direction is used, the other direction automatically becomes unusable. Conventional abstraction systems and methods have bandwidth fragmentation and/or loss of bandwidth whenever there is a need to have instances of asymmetric traffic patterns. Because a true asymmetric pattern is not possible to have as described herein, the conventional abstraction systems and methods leave out the bandwidth in an opposite direction as unusable and configure/provision the next set of timeslots for different concatenation. For example, assume provisioning of two unidirectional circuits having STS-3c (Synchronous Transport Signal) concatenation in a transmit direction and STS-12c (Synchronous Transport Signal 12c) in a receive direction on an OC-48 (Optical Carrier 48) line, then the first STS-3c can be used in the transmit direction on timeslots 1-3 and the next set of twelve timeslots (4-15) are used in the receive direction. The timeslots 1-3 are unused in the receive direction while the timeslots 4-15 are unused in the transmit direction causing bandwidth fragmentation and loss.
Further, assume two different connections in a switch, e.g. symmetric or asymmetric with drops and continues, and assume these two different connections belong to different end users, it is not possible conventionally to merge these connections into one manageable connection without hitting traffic and without affecting blocking probability of a switch fabric. That is, either traffic will be hit or blocking probability will increase because of increased usage of channels between ingress to center or from center to egress than the minimum needed. Specifically, this merger involves merging the abstractions and operating on the underlying physical connections based thereon. When the abstractions are merged, the physical connections do not go over the same single center stage, but rather over multiple center stages therefore requiring many more channels which are wasted in the links between ingress and center as well as center to egress switches. Thus, conventional abstraction systems and methods do not allow one traffic pattern to be converted to another without deleting and re-creating, e.g. conversion from symmetric to asymmetric and vice-versa. Conventional abstraction systems and methods do not provide a way for merging and splitting traffic patterns between two different end users within a single network element without affecting traffic and also without affecting the blocking probability. They may re-work the connections but do not guarantee that the connections pass through the same exact center stage for every flow from begin to end and thus causing an increased blocking probability.